如何扩展MPVolumeView路由按钮区域？

// 创建自定义UIView
let customView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 44))
customView.backgroundColor = UIColor.red

// 将自定义UIView添加到MPVolumeView的父视图中
let volumeView = MPVolumeView(frame: CGRect(x: 0, y: 0, width: 200, height: 44))
volumeView.showsRouteButton = false
volumeView.addSubview(customView)
volumeView.sizeToFit()

// 设置自定义UIView的用户交互
customView.isUserInteractionEnabled = true

// 添加点击事件处理逻辑
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(routeButtonTapped))
customView.addGestureRecognizer(tapGesture)

// 点击事件处理函数
@objc func routeButtonTapped() {
    // 弹出自定义的音频输出设备选择界面
    let audioDevices = AVAudioSession.sharedInstance().availableOutputDataSources
    // 处理用户选择的音频输出设备
    // ...
}

// 将volumeView添加到视图层级中显示
self.view.addSubview(volumeView)